In cast molding methods of producing ophthalmic devices, such as ocular inserts and contact lenses, separate mold members are typically used to form each surface of the device. Often a pair of mold members, one of which forms the entire anterior device surface and another of which forms the entire posterior device surface are typically combined to form a device-shaped cavity, and a reaction mixture or polymerizable composition is cured in the device-shaped cavity. After placing the polymerizable composition in a first mold member, the first mold member and a second mold member are placed together or coupled together to form a mold assembly with an ophthalmic device-shaped cavity therebetween. The mold assembly is then cured to polymerize the polymerizable composition, forming the polymeric ophthalmic device in the device-shaped cavity of the mold assembly.
Commonly, a complete mold member, including its entire molding surface, is produced by injection molding a thermoplastic polymer into a mold-shaped cavity. Lathing of mold members in order to form an entire molding surface has also been described. However, the lens design features which can be reproducibly formed in the molding surfaces while still achieving the necessary optical quality molding surfaces can be somewhat limited when the molding surfaces must be formed either by injection molding or lathing. For example, preparing metal molding cavities having intricate patterns engraved into them can be very difficult and expensive, particularly when a large number of metal molding cavities in a large number of lens powers may be required for commercial-scale production. The cost of lathing individual mold members can be prohibitively expensive and time-consuming, particularly at commercial scales. And even when it is possible or economically feasible to prepare such molding surfaces, it may be difficult if not impossible to release a cured polymeric device body from an intricate molding surface without damaging the device body. Thus, there is a need for new low-cost molding surfaces which allow intricate or complicated surfaces to be cast-molded on ophthalmic device bodies, while readily allowing the cast-molded surfaces to be released from the molding surfaces, and for methods of preparing and using these molding surfaces in the manufacture of ophthalmic devices.
All publications, including patents, published patent applications, scientific or trade publications and the like, cited in this specification are hereby incorporated herein in their entirety.